The Pap (Papanicolaou) Test

A Pap test is sometimes called a Pap smear. It can be done along with a HPV test during a pelvic exam as part of cervical cancer screening for people with no symptoms. Or, it can be done as a follow-up test for an abnormal (positive) HPV test or if someone has symptoms that are suspicious for cervical cancer.

What does a Pap smear test for?

A Pap test is a procedure used to collect cells from the cervix (lower part of the uterus) so they can be looked at closely in a lab under a microscope. It tests for changes in cells that might be pre-cancers or cancer.

How is a Pap test done?

The health care professional first places a speculum inside the vagina. The speculum is a metal or plastic instrument that keeps the vagina open so that the cervix can be seen clearly. Next, using a small spatula or brush, a sample of cells and mucus is lightly scraped from the exocervix (see illustration in  What is Cervical Cancer? ). A small brush or a cotton-tipped swab is then inserted into the opening of the cervix to take a sample from the endocervix . If your cervix has been removed (because you had a trachelectomy or hysterectomy) as a part of the treatment for a cervical cancer or pre-cancer, the cells from the upper part of the vagina (known as the vaginal cuff) will be sampled. The samples are then looked at in the lab.

Although the Pap test has been more successful than any other screening test in preventing a cancer, it’s not perfect. One of the limitations of the Pap test is that the results need to be examined by the human eye, so an accurate analysis of the hundreds of thousands of cells in each sample is not always possible. Engineers, scientists, and doctors are working together to improve this test. Because some abnormalities may be missed (even when samples are looked at in the best labs), it’s best to have this test regularly as recommended by the American Cancer Society guidelines .

Making your Pap tests more accurate

You can do several things to make your Pap test as accurate as possible. It's important to ask your doctor or nurse how you need to prepare for the Pap test, including:

• Trying not to schedule an appointment for a time during your menstrual period. The best time is at least 5 days after your period stops.
• Not using tampons, birth-control foams or jellies, other vaginal creams, moisturizers, or lubricants, or vaginal medicines for up to 7 days before the Pap test.
• Not using a douche for 2 to 3 days before the Pap test.
• Not having vaginal sex for 2 days before the Pap test.

Pelvic exam vs. a Pap test

Many people confuse pelvic exams with Pap tests. The pelvic exam is part of a woman’s routine health care. During a pelvic exam, the doctor looks at and feels the reproductive organs, including the uterus and the ovaries and may do tests for sexually transmitted disease. Pelvic exams may help find other types of cancers and reproductive problems. A Pap test can be done during a pelvic exam , but sometimes a pelvic exam is done without a Pap test. A Pap test is needed to find early cervical cancer or pre-cancers so ask your doctor if you had a Pap test with your pelvic exam.

How Pap test results are reported

The most widely used system for describing Pap test results is the Bethesda System (TBS). There are 3 main categories, some of which have sub-categories:

• Negative for intraepithelial lesion or malignancy
• Epithelial cell abnormalities
• Other malignant neoplasms.

You may need further testing if your Pap test showed any of the abnormalities below. See Work-up of Abnormal Pap Test Results.

Negative for intraepithelial lesion or malignancy

This category means that no signs of cancer, pre-cancer, or other significant abnormalities were found. There may be findings that are unrelated to cervical cancer, such as signs of infection with yeast, herpes, or Trichomonas vaginalis (a type of sexually transmitted disease), for example. Specimens from some women may also show “reactive cellular changes”, which is the way cervical cells appear when infection or other inflammation is around.

Epithelial cell abnormalities

This means that the cells lining the cervix or vagina show changes that might be cancer or a pre-cancer. This category is divided into several groups for squamous cells and glandular cells.

Squamous cell abnormalities

Atypical squamous cells (ASCs) This category includes two types of abnormalities:

• Atypical squamous cells of uncertain significance (ASC-US) is used to describe when there are cells that look abnormal, but it is not possible to tell if this is caused by infection, irritation, or a pre-cancer. Most of the time, cells labeled ASC-US are not pre-cancer, but more testing, like an HPV test, is needed to be sure.
• Atypical squamous cells where high-grade squamous intraepithelial lesion (HSIL) can’t be excluded (ASC-H) is used to describe when the cells look abnormal but are more concerning for a possible pre-cancer that needs more testing and may need treatment.

Squamous intraepithelial lesions (SILs) These abnormalities are divided into two categories:

• In low-grade SIL (LSIL) the cells look mildly abnormal. This might also be called mild dysplasia or cervical intraepithelial neoplasia grade 1 (CIN1).
• In high-grade SIL (HSIL) the cells look severely abnormal and are less likely than the cells in LSIL to go away without treatment. They are also more likely to eventually develop into cancer if they are not treated. This might also be called moderate to severe dysplasia or cervical intraepithelial neoplasia grade 2 or 3 (CIN2 and/or CIN3).

Further tests are needed if SIL is seen on a Pap test. If treatment is needed, it can cure most SILs and prevent invasive cancer from forming.

Squamous cell carcinoma: This result means that the woman is likely to have an invasive cancer. Further testing will be done to be sure of the diagnosis before treatment can be planned.

Glandular cell abnormalities

Atypical glandular cells: When the glandular cells do not look normal, but they have concerning features that could be cancerous, the term used is atypical glandular cells (AGC). In this case, the patient should have more testing done.

Adenocarcinoma: Cancers of the glandular cells are called adenocarcinomas. In some cases, the doctor examining the cells can tell whether the adenocarcinoma started in the endocervix, in the uterus (endometrium), or elsewhere in the body.